232 ANNUAL OF SCIENTIFIC DISCOYERT. 



— 10 grains oxide of cobalt, 15 grains oxide of raanganoso, and 

 from 20 to 30 grains protoxide of iron ; Amelliyst — -i to 5 grains 

 carbonate of peroxide of manganese; Gold Topaz — 30 grains 

 oxide of uranium; Emerald — 20 grains protoxide of iron, and 

 10 grains carbonate of copper. — Chemical News. 



Magnesia Crucibles. — According to the " Mechanics' Maga- 

 zine," a patent has been taken out in France for making crucibles 

 from magnesia, which forms the best materials for crucibles to 

 melt platinum, iron, or steel in. They are moulded by pressure, 

 and are then exposed to the heat of an oxyhydrogen flame, by 

 which they are brought to a semi-pasty condition, when the mag- 

 nesia acquires its greatest density, cohesion, and hardness. 



Arsenic in Bismuth. — Dr. Gunning has shown that the metallic 

 bismuth of commerce almost always contains arsenic. This is in- 

 teresting in a medico-legal point of view, and also may explain 

 many obscure affections of the skin, mucous membranes and 

 other organs, in persons who make free use of the various cos- 

 metic powders containing bismuth. 



New Source of Thallium. — A new source of this rare mineral 

 has been discovered in the flue-dust obtained from a sulphuric 

 acid works in Holland, where pyrites from Suhrort is burned. 

 This flue-dust contains about 1 per cent, of thallium. 



Acetylene. — According to Rieth, the imperfect combustion of 

 coal gas, which takes place when the flame of a Bunsen's burner 

 has gone down so as to burn within the tube, has been found to 

 be a rich source of acetylene. The escaping gases are collected 

 by means of a funnel placed over the burner, and connected with 

 an aspirator. The quantity of the silver compound of acetylene 

 obtained from one burner in 12 hours amounted to 100 grammes. 

 — Zeitschr.f. Chem. 



A NEW PROCESS FOR PRESERVING FOOD. 



At a recent meeting of the Massachusetts Institute of Technol- 

 ogy, Dr. Sim, of Charleston, S. C, gave an account, with ex- 

 periments, of his new process for preserving meats. 



Putrefaction is nature's process for returning organic to inor- 

 ganic matter, and this is effected by dialyzation or change in the 

 proj)ortions of the gases of which the former is comp(^sed. In 

 meats this is brought about, as generally admitted, by the action 

 of minute animalcules, whose germs float in the air and permeate 

 the animal tissues. Soon after death come the monads and the 

 bacteriums, Avhich commence the process. These require oxygen, 

 and, having taken this, they die. Next come the vibrios, which 

 do not require oxygen for their development, and under their 

 influence putrefaction goes on rapidly. If, therefore, we can pre- 

 vent the vivification of these germs, we prevent or arrest putre- 

 faction. 



Sulphurous-acid gas will do this, but it is evanescent and cannot 

 be fixed. Though tlieoretically the best, it is not available in 

 practice, being effectual only while it is in contact with the mate- 



